Skyrmions arise in chiral magnetic systems from a competition
between collinear magnetic order (driven by Heisenberg
exchange and anisotropic interactions) and non-collinearity
caused by Dzyaloshinskii-Moriya (DM) interactions.
Theoretical studies, including Monte Carlo simulations,
of the two-dimensional classical spin model demonstrated that
in chiral magnets with strong DM interaction, skyrmions appear
in the presence of a magnetic field [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}.
Following MnSi, skyrmions have been observed in bulk samples
of other non-centrosymmetric \(B20\)  compounds [10]}
such as Fe1-xCoxSi [11]}, [12]},
FeGe [13]}, [14]},
and MnGe [15]}, [16]}, [17]}
where intrinsic DM interaction drives non-collinear order.
Skyrmions also have been observed in an insulating chiral-lattice magnet
Cu2OSeO3 [18]}.
More recently, artificial heterostructures comprising of thin films
of ferromagnetic materials and heavy metals with strong spin orbit
coupling (SOC) have emerged as a versatile platform
for controllably generating skyrmions[19]}, [7]}.
Here broken inversion symmetry
coupled with strong SOC generates an effective DM interaction at the interface
which can be tuned over a wide range by careful material selection.
Experiments on interfaces of Fe and Fe/Pd thin films
on Ir(111) system have shown that atomic size skyrmions
can be engineered with the help of higher-order interactions such as
the ring exchange [21]}
or due to the presence of longer-range competing interactions [22]}.
Furthermore, innovative multi-layer stackings of Ir/Fe/Co/Pt thin films
lead to the strengthening of interfacial DM interactions and
resulting in small sized skyrmions as compared to the bulk chiral magnets
 [23]}, [24]}.
The effect of skyrmions on physical properties is most pronounced
when their sizes are small. Hence we have used artificially large values of
DM interaction that generates small, lattice scale skyrmions.
Even though most experimental systems yield skyrmions
that are much larger than the lattice constants – we believe
similar effects will be observed in systems with large sized skyrmions,
but in weaker forms.
